Sand-blowing machine

ABSTRACT

A sand-blowing machine having a sleeve in the form of a shell made as a helical spiral with a corrugated surface, the coils of the spiral being in contact with each other over the corrugated surface and forming at the places of contact openings adapted for the passage of air.

United States Patent [1 1 Taburinsky et a1.

[ SAND-BLOWING MACHINE 22 Filed: June 10, 1911 211 Appl. No.: 151,753

[52 user. .Q ..164/200 Int. Cl. B22c 15/22 July 24, 1973 [58] Field of Search 164/19, 22, 200, 164/202, 165, 186, 201, 207, 212, 230, 232, 233, 261

[56] References Cited UNITED STATES PATENTS 2,839,798 6/1958 Hinrichs 164/202 2,861,301 11/1958 Haber1in..... 164/200 2,928,147 3/1960 Hansberg.... 164/202 X 3,328,852 7/1967 Ellms 164/212 X Primary ExaminerJl Spencer Overholser Assistant Examiner-John S. Brown Att0rney-Waters, Roditi, Schwartz & Nissen [57] ABSTRACT A sand-blowing machine having a sleevein the form of a shell made as a helical spiral with a corrugated surface, the coils of the spiral being in contact with each other over the corrugated surface and forming at the places of contact openings adapted for the passage of an.

3 Claims, 6 Drawing Figures UQU 1 SAND-BLOWING MACHINE The present invention relates to the field of foundry practice and, more particularly, it relates to sandblowing machines designed for the manufacture of cores and moulds.

Extensively used at present are sand-blowing machines comprising a crosspiece which includes a working container with a corrugated sleeve and inlet and exhaust valves, said crosspiece being rigidly connected to a bedplate accommodating a pressure table. The crosspiece supports means adapted for charging the sand to l the container and having a hopper for the sand and a gate-valve mechanism to close the working container, as well as a nozzle adapted for the supply and distribution of the sand in a core box or mould.

Core or moulding sand is charged inside the sleeve of the working container from the charging hopper with the gate valve open. The charging operation completed, the gate valve is closed and the table urges the core box against the nozzle, whereupon one or several inlet valves are open through which air is supplied to the working container and from the latter, via openings in the shell, to the inside of the sleeve. Under the effect of compressed air, the sand is supplied through the nozzle to the core box or mould and packed there. Following the packing of the sand, the exhaust valve is opened through which spent air is discharged into atmosphere, after which the pressure table with the core box is lowered and a core removed from the box.

In such known machines, the openings in the shell for the passage of compressed air inside the sleeve are made as milled slots about 0.4 mm wide.

Such sleeves require much labor in their manufacture (for example, in a sleeve having a capacity of 100 liters slots are to be milled whose total length exceeds 100 m) and the sleeves are short-lived due to the fact that air exhausted through the slots in the sleeve carries therewith rather large particles of sand causing abrasion wear of the slots.

There is also known a sand-blowing machine designed for the manufacture of cores and moulds, wherein the shellis made as a helical spiral between whose coils openings are provided for the passage of air from the container to the sleeve.

In such sand-blowing machine, the clearances between the coils of the spiral serve for the supply of air inside the sleeve. The size of the clearances can be adjusted by compressing or stretching the spiral.

This known sand-blowing machine is disadvantageous in that it is impossible to obtain uniform and adequately small clearances between the coils of the spiral, which results in a spontaneous uncontrolled distribution of air supplied to the sleeve and interruption of the process of the sand discharge from the container.

Due to the afore-described disadvantages, the known sand-blowing machine provided with a sleeve as described above is not practical.

It is an object of the present invention to develop a sand-blowing machine with asleeve whose construction makes possible an unlimited reduction in size of openings between the spiral coils and facilitates the required arrangement of said openings over the surface of the sleeve shell.-

It is another object of this invention to render the manufactureof the sand-blowing machine according to the invention less labor-consuming. I

The above and other objects of the invention can be attained in a sand-blowing machine for the manufacture of cores and moulds, disclosed herein and comprising a bedplate with a pressure table, which bedplate is rigidly connected to a crosspiece accommodating means for charging the sand and a nozzle through which the sand is fed to a moulding flask or core box, the crosspiece supporting thereinside a working container and valves adapted for the inlet of compressed air into and exhaust of spent air out of the container, said working container comprising a sleeve which has a shell made as a helical spiral between whose coils openings are provided for the passage of air from the container to the sleeve. According to the present invention, the spiral of the sleeve has a corrugated surface, while its coils are in contact with each other over said corrugated surface so as to form between the places of contact the openings for the passage of air.

It is preferred that one of the contacting surfaces of the spiral be made corrugated.

This will help simplify the construction and reduce the amount of labor involved in the manufacture ofthe spiral shell of the sleeve.

It is also preferred, with a view to better circulation of coolant, that the spiral be manufactured from hollow material in order to maintain the required temperature of the sand in the sleeve.

The present invention will be more apparent upon considering the following detailed description of a preferred embodimentthereof, taken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates the sand-blowing machine in accordance with the present invention, in partial longitudinal section;

FIG. 2 is a longitudinal sectional view of the sleeve for the working container of the sand-blowing machine according to the present invention, manufactured from solid profile material; I

FIG. 3 is a section taken on line III-III of FIG. 2;

FIG. 4 is a section taken on line IV-I of FIG. 3;

FIG. 5 is a longitudinal sectional view of the sleeve for the working container of the sand-blowing machine according to the present invention, manufactured from hollow material; and

FIG. 6 is a section taken on line VI--VI of FIG. 5.

Referring now to FIG. 1 of the accompanying drawings, the sand-blasting machine according to the present invention has a bedplate l with a pressure table 2, and connected to the bedplate via column 3 is a crosspiece 4. Accommodated inside the crosspiece is a working container 5 which houses a sleeve 6 and inlet valves 7 and exhaust valves 8. At the lower portion of the container is secured a nozzle 9, and on the upper portion of the crosspiece is mounted a vibrating hopper 10 for charging sand, and a gate-valve mechanism 11 for opening the throat of the working container when the sand is being charged and for closing said throat when the air inlet valve 7 is opened.

A core box 12 (or a moulding flask) is placed onto the pressure table of the bedplate.

The sleeve 6 (cf., FIGS. 1, 2) of the working con tainer of the sand-blowing machine according to the invention comprises a shell made as a singleor multiple-thread spiral 13 of material of a circular crosssection. The spiral material has acorrugated surface. The sleeve is mounted in upper flange l4 and lower flange 15, said serving for setting and .securing the sleeve in the working container of the machine. Several tie pieces 16 are utilized to prevent the coils of the spiral from coming apart and to impart rigidity to the sleeve. The tie pieces and flanges are connected to the shell by means of welding or in some other suitable manner.

/ The surface of the spiral material is made corrugated for example, by knurling. When so doing, recesses 17 (cf., FIGS. 3 and 4) in the corrugated surface may have a required depth and spacing (pitch) in different portions of the shell in accordance with requirements placed upon the sleeve.

In order to reduce the labor involved in the manufacture of the sleeve, only one of the contacting surfaces of the spiral is made corrugated.

The coils of the spiral shell are made to be in tightly fitting relation to each other so that the openings 17 adapted for the passage of air into the sleeve are formed at the joint of the coils owing to the recesses in one of the contacting surfaces of the spiral 13.

In those cases when the sand is to be heated or cooled inside the working container (for instance, cooling is required when manufacturing cores in heated boxes in accordance with the Hot-box process), the shell of the sleeve is formed from hollow material (cf., FIGS. 5 and 6) and coolant is pumped therethrough to heat or cool the sleeve and, consequently, the sand at the same time. For the supply of coolant to the spiral shell of the sleeve, use is made of flanges 18 and 19 hermetically connected with the shell and provided with conduits 20 and 21 for the supply and removal of coolant.

As shown by experience, the sand-blowing machines of the invention provided with sleeves having spiral shells are efficient and the quality of the cores produced are equal, and even superior, to those of the machines employing conventional sleeves with slit openings in the shells. It has also been found that no accumulation or hanging of the core sand can be observed on the inner surface of the sleeve between the coils of the spiral.

What is claimed is:

1. A sand-blowing machine for the manufacture of cores and moulds, comprising: a bedplate with a pressure table; a crosspiece rigidly connected to said bedplate, means on said crosspiece for charging sand and a nozzle on said crosspiece through which the sand is fed to a moulding flask or core box, said crosspiece having thereinside a working container and valves adapted for the inlet of compressed air into and exhaust of spent air out of the container; said working container comprising a sleeve which has a shell constituted as a helical spiral of material having a corrugated surface, the coils of said spiral being in contact with each over said corrugated surface so as to form between the places of contact openings for the passage of air.

2. A sand-blowing machine as claimed in claim 1, wherein wherever two portions of the spiral come in contact with each other only one of the contacting surfaces is corrugated.

3. A sand-blowing machine as claimed in claim 1, wherein said spiral of said sleeve is hollow and adapted for circulation of coolant. 

1. A sand-blowing machine for the manufacture of cores and moulds, comprising: a bedplate with a pressure table; a crosspiece rigidly connected to said bedplate, means on said crosspiece for charging sand and a nozzle on said crosspiece through which the sand is fed to a moulding flask or core box, said crosspiece having thereinside a working container and valves adapted for the inlet of compressed air into and exhaust of spent air out of the container; said working container comprising a sleeve which has a shell constituted as a helical spiral of material having a corrugated surface, the coils of said spiral being in contact with each over said corrugated surface so as to form between the places of contact openings for the passage of air.
 2. A sand-blowing machine as claimed in claim 1, wherein wherever two portions of the spiral come in contact with each other only one of the contacting surfaces is corrugated.
 3. A sand-blowing machine as claimed in claim 1, wherein said spiral of said sleeve is hollow and adapted for circulation of coolant. 